Iraqi lawmakers voted Monday to refer to the judiciary a report holding top officials, including ex-premier Nuri al-Maliki, responsible for the fall of second city Mosul, the parliament speaker said.

But there were disagreements over the report, with MPs voting to send it without an official reading, and members of the investigative committee that compiled it complaining that there was no vote to approve the recommendations it contained.

"Parliament voted to refer the (Mosul) file, including facts and evidence and names," to the judiciary, speaker Salim al-Juburi said in televised remarks.

"None of the names mentioned in this report were deleted, and all of them will be sent to the judiciary. An investigation and follow up and accounting of all those who caused the fall of Mosul will be carried out," Juburi said.

Former prime minister and current vice president Maliki was the most senior and controversial of those named responsible in the report for the Islamic State jihadist group's takeover of Nineveh province capital Mosul in 2014.

Investigative committee members Hanin Qado and Ammar al-Shibli both said the committee did not vote on the recommendations within the report.

Qado, a member of the Shabak minority, said the report was not read in parliament "due to differences on the recommendations, because there was no vote on the recommendations within the committee."

"The committee is not neutral," said Shibli, from Maliki's State of Law alliance.

IS launched a devastating offensive on June 9 last year, overrunning Mosul the next day and then sweeping through large areas north and west of Baghdad.

Multiple Iraqi divisions collapsed during the initial assault in the north, in some cases abandoning weapons and other equipment which the jihadists then used to further their drive.

While various top commanders and political leaders have long been blamed for the Mosul loss, the report is the first time that they have been named officially.

Those named include defence minister Saadun al-Dulaimi, army chief of staff Babaker Zebari, his deputy Aboud Qanbar, ground forces commander Ali Ghaidan, Nineveh operations command chief Mahdi al-Gharawi and the province's governor, Atheel al-Nujaifi.